A solid sphere, of radius R acquires a terminal velocity v1 when falling (due to gravity) through a viscous fluid having a coefficient of viscosity η . The sphere is broken into 27 identical solid spheres. If each of these spheres acquires a terminal velocity, v2 , when falling through the same fluid, the ratio ( v1/v2 ) equals:
a. 9
b. 1/27
c. 1/9
d. 27